48 FHE AUDUBON “BULLE Tis 
Pie ten, 
€ 
te , 2 ~ - a 
o%, 4 
ns ee . 
iy ey zr, “* 
ae 
‘We 
WK 
<> 7 Pha 
NBT iy ON 
AE CNB 8 : 
- 
ee 
Ht 
scale. Wg. Re 
: FRI: 
OS pen 



> 
Photo by Orpheus M. Schantz 

Map.te Hitt RAvIne 
and delighted to find numbers of birds feeding, and if you listen to their 
cheerful conversation you will discover that they are apparently quite 
comfortable, even in zero weather. 
In many forested areas the surface is too level for ravine formation, 
but where the land is more broken or undulating, the ravines sink deeper 
and deeper and often are of such depth that the tops of tall trees do not 
reach the level of the rims. 
The ravines on the shore of Lake Michigan north of Chicago, have 
long been famous for their treasures of plant life, and more recently, 
since the coming of the cardinal grosbeak to our region, they have fur- 
nished shelter for this hardy, year-round resident against the rigors of 
the wind-swept North Shore. 
In the forest preserves at Chicago Heights is a deep ravine in which 
is found the only colony of buckeye trees in Cook County. An old 
ravine among the Palos Park hills has a wonderful growth of sugar 
maples, butternut, ironwood, and other interesting trees which are only 
found where the soil has reached a certain condition necessary to their 
requirements. 
At the mouth of the Palos ravine is the famous swallow bank, where 
regularly each season a colony of bank swallows makes its summer 
home. This bank of loess is known to geologists and ornithologists. 
